Transcript Indicators of Climate Change

Indicators and Effects of Climate Change
Indicators and Effects of Climate Change
The largest factor affecting climate change is global warming.
Global warming refers to the increase in the average
temperature of the atmosphere and oceans that has been
measured over the past 100 years.
The rate of increase has accelerated since the 1960s. Some regions on Earth
have experienced more warming than others and some have actually grown
cooler during this period. The warming trend is obvious by examining
temperature data as well as indirect evidence such as melting glaciers.
Major Indicators of Climate Change
1. Global Warming
2. Changes Polar and Glacial Ice
3. Sea Level Rising
4. Ocean Acidity
Other Indicators of Climate Change
5. Health
6. Changing Wind and Precipitation
7. Deforestation, Desertification, Wetland loss)
Changes in Polar and Glacial Ice
Satellite measurements have shown that large volumes of ice in Greenland and
the Antarctic have been melting at higher rates in recent years.
Example: The West Antarctic ice sheet has been losing 65 km3 per year. That
amount of melting releases enough water to raise sea levels by about 0.16 mm
per year.
Impacts of Melting Ice
Melting ice raises sea levels, but it also affects the habitat of animals such as seals
and polar bears.
Polar bears depend on large areas of sea ice to hunt their prey. As warmer
temperatures melt sea ice and transform the arctic biome, polar bears in some
parts of their range may be starving or ranging farther to find food. In 2007, the
Wildlife Conservation Society began studying satellite and weather data collected
over 30 years to identify how sea-ice habitats are changing. This information will
help scientists and policy makers decide what areas to protect as polar bear
habitats.
Impacts of Melting Ice
The culture and lifestyle of Canada’s Inuit
population is closely tied to the environment of
the Arctic and its wildlife. The traditional
lifestyle of Inuit peoples involves travelling and
hunting on sea ice.
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Thinning and disappearing sea ice has made
travelling dangerous and may make hunting for
food or income less predictable.
Sheila Watt-Cloutier
Answer the following questions in your notebook.
1. Who is she?
2. What is her job?
3. What schooling has she done?
4. What are her concerns about climate change?
Answer the questions and then we will have a
class discussion.
Rising Sea Level and Ocean Acidity
Oceans are a major part of Earth’s climate system, so any changes in the oceans are a cause for
concern. Scientists are particularly concerned about sea level and ocean acidity.
Table 7.2 Effects of Climate Change on Earth’s Oceans
Indicator
rising sea
level
Cause
About half of this increase is due to the
observed melting of glaciers and
icecaps. The other half is a result of the
thermal expansion of seawater due to
increased temperature.
rising ocean Scientists estimate that the oceans have
acidity
absorbed about half of all carbon
dioxide produced from fossil fuel
emissions over the past 200 years.
Some of the dissolved gas forms
carbonic acid, which lowers the pH of
the water. Lower pH means that the
water is more acidic.
Effects
As sea level rises, more land will be
covered by water. Many of the world’s
largest cities are located in coastal regions,
so large populations of people will be
displaced by rising seas.
Rising acidity threatens the ability of
corals and other organisms to build shells
and hard skeletons and the ability of fish
and plankton to reproduce. The success of
commercial fishers who supply food to
humans may also be affected, and lowlying islands and coastal areas would be
more vulnerable to storms.
Activity 7-4
Acidity and Coral Reefs (p. 293)
Rising Sea Level and pH
The average sea level has risen between 10 and 15 cm over
the past 100 years due to melting of ice of glaciers.
As parts of the
world’s oceans
become warmer,
changes in ocean
pH and in sea level
have occurred. The
oceans are
becoming more
acidic which affects
coral reef
formation.
Climate and Health
Changing climate increases the risk of disease and infections, but
also the risk of injury or death due to extreme weather.
Increasing temperatures affect the amount of dust in the air, the
growth of mold, and the release of pollen by many plants.
As the air quality worsens, people who have allergies or other
respiratory difficulties may have to reduce their outdoor
activities.
Case Study
The Walkerton Water Tragedy
Read the case study on pages 294295 of your textbook and answer the
three questions on page 295 in your
notebook.
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Changing Wind and Precipitation Patterns
Changes in heat distribution over
Earth’s surface have led to changes in
wind patterns.
The speed, frequency, and direction
of winds over Earth’s surface have
fluctuated unpredictably for several
years.
Researchers believe that unusual
wind patterns have helped increase
the melting of ice in the Arctic.
High temperatures increase the rate of evaporation. When warm, moist air rises and
cools in the upper atmosphere, it produces rain or snow. Since 1948, average annual
temperatures across Ontario have increased by as much as 1.4oC. Average annual
precipitation has also increased over this period. The total number of days per year
on which precipitation falls has also increased. In northern parts of the province, a
significant increase has occurred in the number of snowfalls and the quantity of snow
during autumn.
Desertification, Droughts, and Other Outcomes
An increase or decrease in
precipitation affects the levels of
reservoirs and ground water
used for drinking water.
Declines in precipitation can
lead to desertification – the
spread of deserts that have a
reduced capacity to support life.
Storm Intensity and Frequency
Every year, flooding, heavy rains, and strong winds cause
extensive damage to buildings, bridges, and roads. Storms also
disrupt electrical service and put people in physical danger.
Due to climate change, warmer seas hold now hold more energy
to convert into stronger storms.
Changing Biomes
As climate conditions change, the plants and animals that are
adapted to a particular region may no longer be able to survive
there.
The scientists concluded that more than one million species are
threatened with extinction worldwide as a result of climate
change.
http://naturecanada.ca
http://edf.org
http://wildernesscommittee.org
Deforestation
The removal of trees and forests
from an area is known as
deforestation.
A shrinking forest area reduces
the amount of carbon dioxide
(CO2) absorbed from the
atmosphere by photosynthesis.
Thus, loss of trees affects climate
by increasing the amount of
carbon dioxide in the air.
Shrinking Wetlands-and Efforts to Save Them
Freshwater ecosystems supply water for human needs, as well as
playing an important role in regulating climate. Wetlands include
marshes, bogs, fens, and swamps.
These ecosystems store and filter water. They are also habitats
for plants that remove carbon dioxide from the air, and for a
variety of animals.
Lower water levels in the Great Lakes will dry out wetlands
around the shoreline, reducing habitat for wetland species of
plants and animals.
Conservation initiatives are being undertaken involving
cooperation between the Canadian and United States
governments.